The exponential growth of mobile subscribers requires substantial increase of network capacity. However, the capacity of a given network access technology network is limited by the laws of physics. The current cellular network deployed, such as 3G, LTE, LTE-A, suffers from limited licensed spectrum availability restraining the potential capacity increase. Small cell technologies, such as Wi-Fi WLAN is ideally positioned to extend the current cellular network capacity. Wi-Fi appeals to many operators as a cost-effective mean of offloading large amounts of mobile data traffic especially indoor where most of the traffic is generated. Operators are already taking advantage of devices supporting Wi-Fi as a tool to meet capacity demands by letting the user offload manually its traffic on standalone networks. This first stage of Wi-Fi off-loading is often associated with a manual hotspot selection followed by cumbersome logging procedures.
With the development of dual mode mobility devices, the focus of WLAN-cellular offload has evolved from purely static, manual, unsecure offloading traffic from cellular (e.g., 3G WCDMA HSPA or 4G LTE) to WLAN at the collocated UE/STA, to dynamic, automatic, secure, and seamless offloading and interworking between WLAN passport HS2.0 STA-AP systems and LTE UE-RAN-EPC networks, yet with mobility and roaming support between HPLMN and VPLMN. Assume that collocated cellular UE and WLAN STA chipsets, on a smart phone device for example, can coexist harmoniously in different bands without interfering each other. Given the assumption, WLAN-cellular radio can be activated at the same time without much concern of cross-interference. Hence intelligence is needed at the device to automatically decide in real time when to turn on both radios, in what order and to what benefit (KPIs), and how to offload traffic in-between them or concurrently use the two radio for better user experience, e.g., to speed up throughput when downloading of the single webpage through two radio interfaces simultaneously, or video streaming by one and voice telephony calling by another.